Comets and Asteroids Archives

Long period comet C/2006 P1 (McNaught) over the Pacific ocean, as imaged from Paranal Observatory in 2007. Credit: ESO/Sebastian Deiries

Long-Period Comets’ Orbits Reflect Close Passage by Star HD 7977

by Keith CowingJune 26, 2026June 26, 2026

The Gaia mission has allowed researchers to understand the motions of stars like never before, even revealing possible interactions between our Solar System and nearby stars.

Interstellar Comet 3I/ATLAS (NIRSpec IFU) -- ESA (larger Image)

Comets and Asteroids

Webb Finds Clues To The Ancient Origin Of Comet 3I/ATLAS

by Keith CowingJune 23, 2026June 23, 2026

The third identified interstellar comet in human history has a surprising chemical makeup, raising questions as to how common, or unusual, conditions in our own Solar System may be.

Panels (a)–(o) show contour maps of the observed isophotes (black lines) together with the corresponding modelled isophotes (red lines) for the case 𝑟max = 1 cm. For each of these contour panels, a companion plot is displayed to the right, labelled (a′ )–(o′ ), showing a one-dimensional scan extracted along the direction indicated by the straight red line in the corresponding contour map. In these primed panels, the black and red curves represent the observed and modeled brightness profiles, respectively. The 𝑥- and 𝑦-axes in the contour plots are given in pixel units, and the innermost isophote levels as well as the physical dimensions of each image are listed in Tables 1 and 3. In panels (a)–(o), isophote levels increase outward in steps of 1 mag. In the primed panels, the 𝑥-axis is expressed in pixel units and the 𝑦-axis in surface brightness units (mag arcsec−2). -- astro-ph.EP

Astrochemistry, Astrogeology, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Comets and Asteroids, Icy Worlds, Imaging & Spectroscopy, Interstellar, Status Report

Dust Colour, Phase Behaviour, And Monte Carlo Modelling Of Interstellar Comet 3I/ATLAS From 4 au Pre- to 4 au Post-Perihelion

by Keith CowingJune 19, 2026June 19, 2026

We report multi-band photometric imaging observations and Monte Carlo dust tail modelling of the interstellar comet 3I/ATLAS covering a wide range of heliocentric distances, from about 4 au pre-perihelion to […]

An X-ray image of NWA 12774. (Credit: Aaron Bell/CU Boulder)

Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Comets and Asteroids, Impact events, Meteorites & Asteroids, Press Release, Sample Return

Rare Meteorite Provides Evidence Of A Giant Early Planet

by Keith CowingJune 17, 2026June 17, 2026

Four-and-a-half billion years ago, a massive world, possibly as big as the moon or even Mars, orbited our sun before crashing into another celestial body and shattering into rubble.

Locations of the four candidate sites across a 2D map projection of Bennu’s surface captured by the OSIRIS-REx Camera Suite (OCAMS) (Bennett et al., 2021).

Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Comets and Asteroids, Imaging & Spectroscopy, Missions & Hardware, Sample Return, Status Report

Quantifying Surface Heterogeneity Across Asteroid (101955) Bennu using Candidate Site Remote Sensing Data

by Keith CowingJune 13, 2026June 13, 2026

The OSIRIS-REx mission acquired spatially resolved (2-10 m spot sizes) visible-near infrared (VNIR) and thermal infrared (TIR) spectra across four candidate sampling sites on asteroid (101955) Bennu: Nightingale, Osprey, Sandpiper, […]

Schematic illustrating the evolutionary stages of the Eulalia asteroid family. (a) The Eulalia parent body resides near the Jupiter 3:1 mean-motion resonance (J3:1). (b) Catastrophic disruption of the parent body occurs, with approximately 50% of the fragments being directly injected into the J3:1, where they can be driven into the planet-crossing region. (c) Post-disruption dynamical evolution, during which an estimated 50% of the surviving fragments are expected to eventually migrate toward the J3:1 resonance via Yarkovsky thermal forces. -- astro-ph.EP

Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Comets and Asteroids, Extinction events, Habitable Zones, Impact events, Meteorites & Asteroids, Status Report

An 800-Million-Year-Old Impact Shower on the Terrestrial Planets from the Breakup of the Eulalia Parent Body

by Keith CowingJune 7, 2026June 7, 2026

Multiple studies have proposed a substantial surge in large lunar impacts approximately 800 million years ago (Ma).

Initial structure of the Impact Plume 60 s post impact. The impactor strikes from the left, at a 60° angle from horizontal, with the sun located to the right.There is a visible asymmetry in the plume due to the direction of impact; the “hole” on the right side of the plume is a bubble in this 2D slice of a fully 3D plume due to the removal of water vapor-rock mixtures from the simulation during the sampling from SOVA into DSMC codes (Prem et al. 2015). (Top) the plume contains a region of high density (~1022 molecules/m3 ) just above the point of impact, which rapidly drops toward the edges of the plume. (Bottom, left) The high plume densities correspond to short mean free paths for the vapor molecules. (Bottom, right) Comparing this mean free path with the length scale of the density gradient reveals very small Knudsen numbers throughout; the entire plume (except for the very outermost edges) is clearly within the continuum flow regime at this time, rather than the slip-flow, Knudsen, or Free Molecular regimes. -- astro-ph.EP

Astrochemistry, Astrogeology, Atmospheres, Climate, Weather, Comets and Asteroids, Cryobiology, Icy Worlds, Imaging & Spectroscopy, Impact events, Mapping, Geodesy, Cartography, Bathymetry, Mercury, Status Report

Transport of Water In A Transient, Impact-Generated Atmosphere On Mercury

by Keith CowingJune 5, 2026June 26, 2026

Mercury’s polar cold traps host water ice deposits that are likely populated with impact-delivered water via Mercury’s exosphere.

Allen Telescope Array (ATA) at the Hat Creek Radio Observatory in Northern California -- SETI Institute

Astrochemistry, Astronomy & Telescopes, Biosignatures & Paleobiology, Comets and Asteroids, Imaging & Spectroscopy, Intelligence & Language, Interstellar, Press Release, SETI & Technosignatures

SETI Institute Looks for Signs of Technology in Interstellar Visitor 3I/ATLAS

by Keith CowingJune 4, 2026June 4, 2026

Scientists at the SETI Institute searched for technological signals from 3I/ATLAS, the third interstellar object observed in our Solar System.

An artist's impression of a disk of gas and dust formed during the birth of the sun. Credit: NASA/FUSE/Lynette Cook

Astrochemistry, Astrogeology, Comets and Asteroids, Exoplanets, -moons, -comets, Habitable Zones, Mars, Mercury, Meteorites & Asteroids, Press Release, Venus

New Experiments And Modeling On Iron Meteorites Provide Insight Into Young Solar System And Earth’s Building Blocks

by Keith CowingJune 4, 2026June 4, 2026

Habitable planets require life-essential elements, like nitrogen and phosphorus. Understanding how those elements ended up in a planetary body can give insight into the formation of the solar system and […]

Top: coma maps of H2O, CO2, and CH4, computed as the molecular column density from a pixel-by-pixel retrieval analysis for Observations 6, 15, and 6, respectively. The sunward and target velocity directions are denoted by the white arrows. The target centroids, computed as the photocenter in the median-stacked images (Figure 1), are marked with the black points. For H2O and CO2, the white contours correspond to emission levels of 50% and 20% relative to the maximum value and illustrate the slight antisunward extension of the respective comae. The contours are omitted in the CH4 panel, due to the poorer signal-to-noise ratio of the data. Bottom: corresponding median-stacked images across the continuum wavelengths within each fluorescence region. The H2O coma map shows a significant enhancement in the emission level at large nucleocentric distances relative to the dust continuum, indicating extended H2O production within the coma. -- The Astrophysical Journal Letters

Astrochemistry, Astronomy & Telescopes, Biogeochemical Cycles & Geobiology, Biophysics, Biosignatures & Paleobiology, Comets and Asteroids, Icy Worlds, Imaging & Spectroscopy, Interstellar, Press Release

Webb Detects Methane on Interstellar Comet 3I/ATLAS

by Keith CowingJune 2, 2026June 2, 2026

NASA’s James Webb Space Telescope has collected its first mid-infrared chemical fingerprint of an interstellar object during a recent revisit to comet 3I/ATLAS. The team’s results published recently in The […]

Comets and Asteroids

Long-Period Comets’ Orbits Reflect Close Passage by Star HD 7977

Webb Finds Clues To The Ancient Origin Of Comet 3I/ATLAS

Dust Colour, Phase Behaviour, And Monte Carlo Modelling Of Interstellar Comet 3I/ATLAS From 4 au Pre- to 4 au Post-Perihelion

Rare Meteorite Provides Evidence Of A Giant Early Planet

Quantifying Surface Heterogeneity Across Asteroid (101955) Bennu using Candidate Site Remote Sensing Data

An 800-Million-Year-Old Impact Shower on the Terrestrial Planets from the Breakup of the Eulalia Parent Body

Transport of Water In A Transient, Impact-Generated Atmosphere On Mercury

SETI Institute Looks for Signs of Technology in Interstellar Visitor 3I/ATLAS

New Experiments And Modeling On Iron Meteorites Provide Insight Into Young Solar System And Earth’s Building Blocks

Webb Detects Methane on Interstellar Comet 3I/ATLAS

Perseverance Astrobiology Droid Has Completed A Martian Marathon

Machine Learning And Deep Learning For Exoplanet Detection And Atmospheric Characterization With JWST And The Upcoming Ariel Mission

Bioleaching Of Critical Trace Metals By Sphingomonas Desiccabilis: Substrate-driven Selectivity In Earth And Space Analogues

TESS Reveals The Puffiest Exoplanets Ever Found

An Agnostic Machine Learning Model of Photosynthetic Habitability